The objectives of this study are to develop a new portable rehabilitation device with intelligent control to stretch an ankle joint with spasticity and/or contracture repeatedly to reduce spasticity/contracture in neurologically impaired patients. It will stretch the joint to true extreme plantar- and dorsi-flexion until a specified peak resistance torque is reached with the stretching velocity adjusted constantly based on the resistance torque. Once the peak resistance torque is reached, the ankle will be held at the extreme position for a period of time to let the stress relax before it is rotated back to the other extreme position. The stretching velocity will be very slow at the joint extreme positions, making it possible to reach a larger ROM safely, and it will be fast in the middle ROM so the majority of the stretching exercise is not spent in the middle ROM where contracture/spasticity is less significant. The device will also be used to evaluate outcome in multiple aspects including changes in passive ROM, joint stiffness, viscous damping, energy loss, and reflex excitability. The stretching device will provide a useful tool to both the therapists and neurologically impaired patients. In Phase II of this project, we will make comprehensive improvements of the intelligent stretching device and make it ready for commercialization. Mechanical and electronic designs and relevant software will be improved considerably, making it a stand-alone medical device with a user-friendly handheld interface. We will evaluate its use in clinical treatment and outcome assessment in stroke patients with spastic ankle. The overall objectives of the Phase II project are to develop an effective, portable, low-cost, and user-friendly intelligent stretcher, suitable and economical for patients to use in clinic or home and ready for commercialization.